1. Field of the Invention
This invention relates to a lamp apparatus and a blinker for a vehicle wherein a light emitting diode is used.
2. Description of Background Art
In recent years, vehicle lamps that use a light emitting diode as a light source are increasing. A lamp apparatus of the type mentioned uses a plurality of light emitting diodes in one lamp unit in order to secure a sufficient amount of light. Since the light emitting diodes are low in power consumption and have a long life they provide a high degree of freedom in the shaping of a lamp body. The lamp apparatus and blinker of the type described is suitable particularly for an vehicle that is limited in the space available for a lamp body like a door mirror of the type which has a blinker built therein or a motorcycle.
In recent years, a blinker apparatus for a vehicle wherein a light emitting diode is used as a light source is available. A blinker apparatus of the type mentioned uses a plurality of light emitting diodes in one blinker in order to secure a sufficient amount of light.
To the blinker, power from a vehicle power supply is supplied through a blinker relay apparatus. See, for example, Japanese Utility-Model Laid-Open No. Sho 57-5227.
Since a forward voltage necessary to turn on the light emitting diodes is sufficiently low when compared with a vehicle power supply voltage, the vehicle power supply voltage is usually dropped by means of a series of resistors provided for each light emitting diode to adjust the voltage to be applied to the light emitting diode. See, for example, Japanese Patent Laid-open No. Sho 63-222984.
However, in the conventional lamp apparatus for a vehicle described above, the temperature of the light emitting diodes is liable to be raised by heat generated by the series resistors. In addition, in the blinker apparatus for a vehicle described above, since the series resistors are provided in the proximity of the corresponding light emitting diodes in order to suppress an error in the voltage to be applied, upon energization, the temperature of the light emitting diodes is raised by heat generated by the series resistors.
As the temperature of the light emitting diodes becomes high, the forward voltage drops. As a result, increased forward current flows to the light emitting diodes to increase the power dissipation and reduce the life of operation of the light emitting diodes. Further, if the distance between the parts is increased to raise the heat radiation property, then the lamp body is increased in size. An increase in size is difficult when the arrangement space for the lamp body is limited.
As a means for solving the subject described above, a lamp apparatus for a vehicle is provided wherein a light emitting diode is used as a light source and wherein a lamp body case is formed from a material having a high heat transfer property with the light emitting diode being attached to a part of the lamp body case.
With the lamp apparatus for a vehicle, heat generated by the light emitting diode and so forth can be transmitted directly to the lamp body case and easily radiated. Consequently, a temperature rise of the light emitting diode is suppressed, and the forward voltage is stabilized and the lighting forward current can be maintained within an appropriate range.
Further, because the heat radiation property is increased, parts can be arranged densely in the lamp body. Consequently, a miniaturization of the lamp body can be anticipated.